Top Gear's Stig Schools Us in Racing With ... a Go-Kart

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Top Gear's Stig Schools Us in Racing With ... a Go-Kart

The biggest misconception about race car drivers is that our job involves piling through curves as fast as humanly possible. It doesn’t. I’m not sure many of my passengers would have agreed when I took them for a ride as The Stig, but turning is about compromising. Some people find that harder to accept than others.

“Hammerrr!”

This is not the mating call of the lesser-spotted Stigasaurus, rather the piston-rattling caw of a primate better known as Jeremy Clarksonzilla. Jezza makes every car he climbs aboard look small, and they positively shiver when he turns the key.

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Despite his sins as a car surgeon, Jeremy has quite a natural feel for the amount of grip a car has through a corner and regularly consumes it from start to finish. Flying in formation with him requires patience, lots of patience, and admitting to yourself that he can drive around the corner a little bit faster than you.

Unaware until then that Jeremy had defeated a world-class touring car champion, I steeled myself as he described the manner in which he dispatched not just Soper but all manner of racing pros during a time attack around Silverstone’s Grand Prix circuit.

“Soper was in tears,” he continued. “He simply couldn’t believe that some overweight journalist could possibly have beaten him. He drove his nuts off for the rest of the afternoon trying to clip my time, but he couldn’t.”

“How did you manage it?” I asked, kind of knowing the answer.

“I cheated, of course.”

So off we went for a choreographed race and some tandem drifting around our favorite turns at the Top Gear track.

When you run super close to another vehicle, you learn to read its body language and to anticipate where it’s going so that you avoid getting tangled up. From behind it’s easy because you can gauge the attitude of the car in front by how much the front wheels are turning in the bend. If the fronts seem fairly straight inside the wheel arches, it means the car in front is oversteering as the rear tires lose traction, but if the front wheels are visibly turning a lot, it means they are resisting and beginning to understeer.

Even when I was ahead of Jeremy, I noticed his front tires twisting outside of the bodywork and could practically hear him swearing above the tire squeal. We pulled to a halt.

“You’re too fucking slow into Chicago,” he advised. (The Chicago corner is an increasing radius corner that should be taken at low to medium speeds.)

“No I’m—”

“Yes, you are. And it’s making this car understeer like a bloody pig.”

I studied the outside of his front tires, which admittedly were more grained than a photo of Jordan without touch-up. We swapped cars, and Jeremy’s signature was clearly stamped all over the thousand-degree rubber-cum-molasses. Much to his dismay, I proceeded to enter the curves even more slowly to allow the molten tires to recover and effect a perfectly balletic flying exit. I tried explaining the racing credo of “slow in, fast out,” but the resulting conversation would make a sailor blush. If you want to hear my side of the story, please read on.

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Viewing the Curve

In its simplest form, there are three overlapping phases of taking a curve: braking, turning, and accelerating.

To plan these phases, you must make a visual assessment of the approaching bend to gauge the sharpness and direction of the curve, then plan the appropriate speed and line for dispatching it. You continuously update your view of the corner, road surface, and situation as you approach the braking zone. You squeeze the brakes and release pressure as you turn in, all the time looking through the corner to chase the vanishing point.

The vanishing point is the farthest point of the road ahead that you can see and is a good rule of thumb for matching your speed to the curvature. When your viewpoint is extending through a corner at the same rate as your speed, it means the corner is opening with you and matching your speed. If the vanishing point stops moving, it means that the corner is tightening up and you’re going too fast.

On the track we say that the next corner begins before the last one finishes. In other words, we keep one eye permanently on the horizon, so we can plan the next turn well in advance and ensure that we are driving into clear space. Anticipation is another way we “slow down time.”

Rhythm

Taking a corner well depends on a number of factors, but these are all governed by a single principle: rhythm. Once you get a handle on the right way to position yourself for a corner, it becomes a way of life.

Bad positioning will make the car inherently unstable because it will be fighting you all the time and your erstwhile passengers will seek less dangerous pastimes elsewhere.

Timing the moves, swinging the controls, and seeing the situation develop ahead of time closely resembles some of our finest moments on the dance floor. And because there will be less commotion with the machine, driving it requires less energy, and you can focus farther ahead.

Race-car drivers use the rhythm of a circuit to develop a system that guides them from one corner to the next. We call that system the racing line, and although every driver has subtle preferences according to his feel for the beat, it is a universal language for describing the way to maximize a machine’s stability.

The Physics of Turning a Corner: The Tire Vs. Isaac Newton

Sir Isaac Newton’s Third Law of Motion asserted that no object could develop a force greater than that being applied to it. But by stretching in two directions (lengthwise as well as laterally) when introduced to a corner, the modern tire develops forces the combined value of which can exceed the loads being applied to it.

Clever. However, while celebrating its capacity to multitask, one shouldn’t forget that it can never do two jobs as well as it can do one. We therefore separate the process of taking a curve into three phases:

Best braking takes place in a straight line, because weight transfers to the front tires, which aids braking and initial turning power.

Best turning takes place with no braking or throttle. You reduce braking as you start steering. The body of the car will lean over; the weight transfers to the outside tires, creating turning power.

Turning power reduces as acceleration begins. Best acceleration happens in a straight line.

Pursuing this sequence is a whole lot more reliable, and comfortable, than dancing on the pedals.

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Race car drivers are known for being prima donnas with custard for brains and heavy right feet. But in 1958 one of the brethren, an F1 driver named Piero Taruffi, became momentarily possessed by some kind of Einsteinian spirit.

His eyes rolled inside their sockets like the dials of a slot machine, and he spat out an equation for predicting the maximum speed of a car through any given curve—F=mv2/r—then he skipped back to the swimming pool and demanded more sunscreen.

When you’re taking a curve, your car’s tires have four potential enemies, excluding your erratic enthusiasm: the nature of the road surface, the vehicle’s weight, your speed, and the tightness of the bend.

In true game show host style, I will not reveal which of these vital elements is missing from brother Taruffi’s equation until later on. For now, just consider that your tires have to create an equal or greater amount of grip than the centrifugal force—F—of cornering.

Weight: The weight of the car rounding an arc creates a centrifugal force, just like spinning a yo-yo around the end of a string. As any yo-yo champion will tell you, it doesn’t pay to rely on a heavier yo-yo body for yo-yoing or cornering because the heavier the yo-yo, the greater the force trying to shear it away from the string and off into the neighbor’s garden.

When you swing through a corner, the centrifugal force wants to throw the car off the road in the same way, but it meets resistance from your tires, which cling stubbornly to the road surface. If you were to let go of the steering wheel the car would instantly go straight, because the only things forcing it to turn are the front tires. The heavier the car and the more passengers you carry, the more work the tires have to do.

Speed: Alarmingly, the effect of your speed on cornering force is exponential. In the turning equation, your weight is multiplied by the square of your speed!

Bend: In a perfectly planed curve, the apex is exactly halfway through the turn. In the image above, the example at the top shows a theoretically perfect radius (driving line) which with its maximum radius length offers the greatest cornering potential as far as equations are concerned.

A small uplift in accuracy provides a big benefit to the machine.

In the image above, a driver could take this curve at a higher constant speed of 55.2456784 mph using line J by driving like Jezza. However, his tires would have spent all of their potential grip in the process, leaving nothing with which to accelerate onto the straight that follows. The time advantage you gain by traveling faster down the straights significantly outweighs any short-term gains from screeching through the bends. So although it’s been fascinating to swallow a geometry book, you’ll be glad to know that taking a curve is a lot more artful than driving by numbers.

The Racing Line

The racing line is not geometrically perfect. It can best be described as a variable radius, because it sacrifices curve entry in favor of expanding the space available for the exit. You spend a little more time setting up for the curve by turning in a hint later, clipping the apex slightly farther around the curve, and reaping the benefits as you depart.

Slow in, fast out means taking control of the biggest part of the equation—speed—by braking early so that you have enough grip in the middle of the curve to make a clean getaway. The tighter the turn, the harder the tires have to work until they reach their limit, so you brake earlier and harder to give them the stability they need at the apex for when you start to accelerate.

When you look at a curve you might think that there’s nothing to it in terms of choosing the direction you follow. But by making subtle adjustments, you can position the car so that it follows a gentler path.

Race car drivers cut curves to shorten the distance their machines have to travel and increase the radius of their turn. They use the full width of the track because there’s nothing coming the other way and thereby have the maximum possible amount of grip at their disposal. On a road with two-way traffic this is a dangerous and lazy move, and not what I’m suggesting at all.

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Using the available space between the roadside and the white line, you can shape the curvature to your benefit. By turning in from a wider position, accurately cutting in toward the center of the corner, and gradually releasing the steering as you leave, you can potentially drive around it faster, or in safety terms will have more grip in hand to tackle irregularities in the road surface. A small uplift in accuracy provides a big benefit to the machine.

When I raced at Charlotte Motor Speedway in a NASCAR support race, the track conditions would change by the hour depending on the temperature. During the daytime I found that the fastest way around the kidney-shaped oval was to enter the two flat-out turns by turning in quite late, missing the apex by a few feet, and straight-lining the exit. However, at night, when the temperature dropped, the car became unstable and would “walk” toward the wall on my right.

“Get your ass down on that white line,” came a voice from the Rodeo over the radio. It was my first night outing on an oval so I obeyed, ran all the way down to the white border, and listened to the motor perk up on the way out. Longer radius. Duh.

The voice belonged to the NASCAR legend who was Dick Trickle, winner of basically every race around a circle and infamous for smoking during the extended caution periods while the officials scraped the wreckage off the floor.